Gaseous fuel system for automotive vehicle

Abstract

A gaseous fuel system for an automotive vehicle includes a gaseous fuel storage tank and an associated pressure sensor for monitoring pressurized gas contained within the storage tank. A parameter-driven routine monitors the integrity of the tank by tracking filing cycles marked by the increase of the tank pressure from a first threshold to a second threshold. Mitigation actions may be taken in the event that the filling cycles exceed a predetermined number, or in the event that other system integrity monitoring indicates that mitigation is in order.

1. A gaseous fuel system for an automotive vehicle, comprising:
 a gaseous fuel storage tank; 
 a pressure sensor for monitoring the pressure of gas contained within said storage tank and for generating a gas pressure signal corresponding to said pressure; 
 a controller for receiving said gas pressure signal and for recording each filling cycle wherein said pressure signal indicates that the pressure within said storage tank has been increased from below a first threshold value to a value above a second threshold value, with said controller initiating mitigation in the event that the number of recorded filling cycles exceeds a predetermined number of cycles. 
 
     
     
       2. A gaseous fuel system according to  claim 1 , wherein said mitigation comprises limiting the pressure to which the storage tank may be filled. 
     
     
       3. A gaseous fuel system according to  claim 1 , wherein said mitigation comprises limiting the quantity of compressed fuel which may be introduced into the storage tank. 
     
     
       4. A gaseous fuel system according to  claim 1 , wherein said controller initiates mitigation in the event that at least one of the pressure of the stored gas, the temperature of the stored gas, and the temperature of said fuel storage tank exceed predetermined threshold values. 
     
     
       5. A gaseous fuel system according to  claim 1 , wherein said controller determines the quantity of fuel within said storage tank as a function of at least the temperature and pressure of the gas stored in the tank. 
     
     
       6. A gaseous fuel system according to  claim 1 , further comprising a fill valve connected with said fuel storage tank and with said controller, with said controller further being connected to a transmission range sensor such that said controller prevents filling of said fuel system unless said transmission sensor indicates that a vehicle transmission is in a park range. 
     
     
       7. A gaseous fuel system according to  claim 1 , further comprising a fill valve connected with said fuel storage tank and with said controller, with said controller further being connected with a plurality of fugitive fuel gas sensors, and with said controller closing said fill valve in the event that the presence of fugitive fuel gas is detected by at least one of said sensors during refueling. 
     
     
       8. A gaseous fuel system according to  claim 1 , further comprising a fuel transfer line extending from said storage tank to a prime mover, with said transfer line having a fuel pressure sensor connected with said controller, with said controller tracking the pressure within said transfer line when fuel is not being withdrawn from said storage tank. 
     
     
       9. A gaseous fuel system according to  claim 1 , further comprising a fill valve having a variable fill orifice operated by said controller. 
     
     
       10. A gaseous fuel system according to  claim 1 , further comprising a communication link embedded in said controller for advising an electronically controlled fuel filler of at least one fuel fill parameter. 
     
     
       11. A gaseous fuel system according to  claim 10 , wherein said controller and said communication link advise said electronically controlled fuel filler as to the maximum pressure to which said fuel tank is to be filled. 
     
     
       12. An automotive vehicle comprising:
 a gaseous fuel storage tank containing a quantity of compressed gas; 
 a prime mover comprising at least one rotating machine and an associated transmission, with said prime mover being fueled by gaseous fuel from said fuel storage tank; 
 a pressure sensor for monitoring the pressure of gas contained within said storage tank and for generating a gas pressure signal corresponding to said pressure; and 
 a controller for receiving said gas pressure signal and for recording each filling cycle wherein said pressure signal indicates that the pressure within said storage tank is increased from below a first threshold value to a level above a second threshold value, with said controller initiating mitigation in the event that the number of recorded filling cycles exceeds a predetermined number of cycles. 
 
     
     
       13. An automotive vehicle according to  claim 12 , further comprising a fill valve connected with said fuel storage tank, with said fill valve having a sensor for detecting the presence of a fill nozzle and for sending a refueling signal to said controller, and with said controller preventing movement of said vehicle in the event that said refueling signal is present. 
     
     
       14. An automotive vehicle according to  claim 12 , wherein said prime mover comprises a reciprocating internal combustion engine and an associated transmission. 
     
     
       15. An automotive vehicle according to  claim 12 , wherein said prime mover comprises a fuel cell, and electrodrive motor, and an associated transmission. 
     
     
       16. An automotive vehicle according to  claim 12 , wherein said compressed gas comprises natural gas. 
     
     
       17. An automotive vehicle according to  claim 12 , wherein said compressed gas comprises hydrogen. 
     
     
       18. A method for monitoring the operating condition of a gaseous fuel storage system and an associated prime mover, comprising the steps of:
 monitoring the number of filling cycles of a gaseous fuel storage tank by recording each instance in which the gas pressure within the tank is increased from below a first threshold value to a value above a second threshold value; 
 monitoring the integrity of a fuel transfer line extending from said storage tank to said prime mover by tracking the pressure within said transfer line when fuel is not being withdrawn from said storage tank; and 
 initiating mitigation in the event that either the number of filling cycles exceeds a predetermined number, or in the event that the tracked pressure within said fuel transfer line decreases at a rate in excess of a predetermined maximum permissible rate. 
 
     
     
       19. A method according to  claim 18 , wherein said mitigation comprises the step of limiting the maximum filling pressure of said storage tank in the event that said predetermined number of filling cycles has been exceeded. 
     
     
       20. A method according to  claim 18 , wherein said mitigation comprises the step of limiting the discharge of gas from said storage tank into said fuel transfer line in the event that said tracked pressure decreases at a rate in excess of said predetermined maximum permissible rate. 
     
     
       21. A gaseous fuel system for an automotive vehicle, comprising:
 a gaseous fuel storage tank; 
 a plurality of sensors for determining the values of a plurality of operating parameters of said gaseous fuel system, with said sensors including at least a pressure sensor for determining the gas pressure within said storage tank; 
 a controller operatively connected with said plurality of sensors, with said controller comprising a parameter-driven routine, using as input data at least the output of said pressure sensor, for monitoring the operating condition of said fuel storage tank; and 
 wherein said controller monitors the useful life of said storage tank by recording each filling cycle wherein the output of said pressure signal indicates that the pressure within said storage tank has been increased from a first threshold value to a second threshold value. 
 
     
     
       22. A gaseous fuel system according to  claim 21 , wherein said controller initiates mitigation in the event that the number of recorded filling cycles exceeds a predetermined number of cycles.